A coke-oven door normally has a massive metallic door body adapted to fit against the doorjamb of the respective coke oven. This door body carries on its inner face a refractory plug that extends into the respective coking chamber and directly engages the charge in this chamber.
In order to prevent the dangerous vapors created during the coking operation from escaping from the oven an annular seal is normally provided extending around the edges of the door and which engages the annular doorjamb surface. This seal is normally made of metal to be able to resist the high temperatures of operation of the coking oven.
Practice was normally to ensure a snug fit between the seal strip and the doorjamb simply by mounting it for limited displacement toward and away from the doorjamb. Once the door was fitted tightly to the doorjamb, normally by extensive and heavy-duty latching arrangements, the seal is pounded by the operator of the furnace into tight contact with the doorjamb surface. This procedure has been found to be relatively unsatisfactory not only because it requires considerable work so that a proper seal is ensured, but even at best the seal frequently leaks at several locations.
According to printed German application No. 1,018,390 of Paul Van Ackeren it is known to provide a Z-section seal having one leg clamped to the edge of the door and another leg urged by a plurality of spring-loaded pushers toward the doorjamb surface. These pushers each consist of an element engaging the seal and displaceable toward and away from the doorjamb on the door body, a spring engaging this element, and a screw threaded in the door body capable of increasing or decreasing the compression of the spring between it and the element. Such an arrangement ensures a relatively tight fit so long as the door body remains perfectly parallel to the doorjamb.
It is, however, fairly common for the door bodies to become distorted due to the effects of heat. In this situation, therefore, the above-described seal systems will leak considerably, although the availability of some biasing force in the second-described system does allow minor distortions to be compensated for. Even with such compensation, however, the amount of force with which the seal is pressed against the doorjamb is decreased considerably in a region where the door body has distorted away from the doorjamb.
Another system is described in U.S. Pat. No. 3,974,038 of Tucker. Here, once again, a seal strip is urged by a plurality of spring-loaded arrangements against the doorjamb. Extending axially through the center of the biasing screw is a rod which allows the user readily to ascertain the position of the seal at each biasing unit relative to the respective biasing unit. This system, however, suffers from the same disadvantage as the other above-described systems in that thermally caused distortions of the door body will pull the entire arrangement, including the biasing unit, away from the doorjamb in some spots and push it toward the doorjamb in other spots. The result is a potential leak.